Hey guys I have a 2001 V10 with 120,000 miles. Its starting to run rough so i am thinking it is time for new spark plugs. While i am there i want to change the coils as well. I know the general consensus is that motorcraft spark plugs are the best for the V10 but what COPS do you guys recommend?

 

I chose motorcraft also. replaced all 10 because 7 had weak spark. no problems with any of them

 

I chose motorcraft also. replaced all 10 because 7 had weak spark. no problems with any of them yet

 

Looking at 1AAuto.com...WOW! $500 for a set of 10 Motocraft COPs vs $100 for non-Motocraft. For this type of stuff, I always (or usually) go with Moto stuff. But I can sure as hell see why folks are tempted to choose otherwise.

I had no idea Motocraft was so much more for COPs.

 

damn that's a **** load i saw 8 accel cops on summit racing for 250. don't really want to drop 500 on cops but i also don't want to have to replace cheap cops 2 years down the road

 

found these not sure if its the right part number but would only be 310 instead of 500.

 

I learned the hard way anything other than Motorcraft is at best a crap shoot for the longer term.

Yes there are no shortages of cheaper COP's but how often do you want to change one more that's failed too soon?

Yes $500 for 10 COP's is sticker shock but give careful consideration to why something so similar is significantly lower priced. Its not because the seller is a good guy---its because somewhere along the line huge compromises in quality have been made.

The temptation to go cheap tends to bite one in the butt all too often, IMHO anyway.

 

You do not have to replace any COP until it fails . Carry a spare Motocraft (or Standard brand-Makers of Motocraft) with you , just in case .

 

I replaced all 10 of mine with Accels. Within two weeks I replaced all of them with Standard COPs. Too many of the Accels died in the first two weeks. They did cost less, though.

 

Ok, dumb question from the uninitiated. How does one know when a COP has failed? Rough idle? Is there an electrical (ohm) test?

 

Actually it is a very good question .

Small percentage of trucks (like mine ) are OBDII compliant , in that case there should be a CEL light indicating misfiring cylinder number .

I do not think that OBDI type trucks will indicate the misfiring cylinder . One way to check is to remove one COP at a time until there is no change .
Not all misfirings are due to bad COP , there are other reasons ( bad spark plug, arcing rubber boot, wiring , acting injector, etc. ).

A youtube presentation by Autolite put it this way : If spark plugs left too long , their gap would be much larger ( for 2-valve V-10 : 0.054 inch new plug gap , my plugs were about 0.070" gap at 75K miles when I changed them) . COP has to create higher voltage to jump the bigger gap which will result in hotter running COP and it will fail internally .

There is a check with Ohm-meter . The primary circuit resistance : 0.55 ohm , the secondary resistance 5500 ohms.
There had been some reports that a COP could pass the resistance test when it is COLD and it may misfire when it gets HOT .

 

usually a cop failure will be an intermittent miss at idle and cruise, it will run rough and then all of a sudden run fine OR just miss all the time.
I took my old f150 in for that, I also wanted an oil change, so the oil change guy was out of synthetic, he drained the oil and dropped it off the lift and went to lunch, the mechanic who was to change the coil started it and drove it and fried the engine with no oil, so I got a new 5.4 out of the deal. They almost tried to blame it on me but I was there when they told me they were out of synthetic, they called me and told me I had a rod knock, I told them they were full of it and called them out. They played my Ford dealer and got it covered under warranty with no deductable on me. I don't think any aftermarker COP will be any better than the stock, in my experience unless forced induction the factory stuff is best, look at the Ford TFI module, the best one is the Factory one at any price, a hotter spark on these modern enginges is only good on heavily modified, boosted or high compression engines, it will make no difference on a stocker or lighthtly modified one.

 

Good question indeed!

The resistance check tends to be highly inaccurate to a COP's performance in the engine. If one doesn't have access to a code scanner with live data or what's known as Mode 6 info the unplug one at a time is probably as accurate as need be for most people.

My '00 will throw a code for known misfires of Grantelli COP's however my '03 showed a pending misfire code for the #1 cylinder but not CEL.

Wakeon makes a COP tester that's a bit too expensive IMHO for what it does. A scanner with live data would be a better expenditure.